Process of casting metals



of Toledo, Lucas Patented May 8, 1923.

PAT

OFFHCE.

HUBERT A. MYERS, OF TOLEDO, AND ARTEEMES D. STRAW, OF WAUSEON, OHIO,ASSIGNORS, BY DIRECT AND MESNE ASSIGNMENTS, TO THE HUBER! A. MYERSCOMPANY, OF TOLEDO, OHIO, A CORPORATION OF OHIO. I

PROCESS CASTING METALS.

No Drawing.

To all whom it may concern:

Be it known that we, IlUm-urr A. MYERS and Amenities D. STRAW, citizensof the United States, and residents, respectively, County, Ohio, andVauseon, Fulton County, Ohio, have made an invention appertaining toProcesses of Castin Metals; and we do hereby declare the fol owing to bea full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same.

()ur invention relates to the art of casting metals in permanent molds,and it has for its object the rapid and economical pro duction ofcastings, uniformly superior in finish and quality.

It is a matter" of common knowledge that the casting of metal in coldmetallic molds will produce hard, brittle castings and that a coldmetallic mold will cause the metal to rapidly congeal'and crystallizelocally,

and thus prevent any but the plain'est kind of castings from conformingto the matrix of the mold. Efforts have been made to avoid thesedifiiculties or objections by heating the mold, but with the result thatthe castings would adhere or stick to the surface of the mold andprevent delivery of the castings therefrom. Attempts have also been madeto prevent adherence of the castings to the mold, whether hot or cold,by coating the molding surface with various materials, such as graphite,aluminum paint, I

and similar surfacing materials, but these have not proven satisfactoryor efficient in practice. ()ne objection to the usual surface coating isthat in pouring any but the simplest castings, the coating will bebrushed from the prominent parts of the mold and the flowing metal willin a short time cut away portions of the mold and thus destroy itsutility. Other objections are that some of the coating materialsheretofore used cause pitting of the castings and others will not adhereto the mold at the high tem peratures necessary for producing soft,perfeet castings.

The object of our invention is to produce in permanent molds, castingswith smooth,

Application filed January 27, 1921. Serial No. 440,501.

perfectly formed surfaces, whether the molds are hot or relatively cold,and in carrying out our invention we so treat the mold that theprotecting material used will not be removed or destroyed or itsefficiency injuriously affected either from the heat of the mold or fromthe contact and flow of the molten metal.

()ur invention is based upon the discovery that the use of certaingasifiable or vapor forming metalliferous substances in the body, or ator On the surface, of the mold, will produce smooth, perfect castings,free from pits or blow-holes and will prevent the adherence of the metalto the mold, although the mold is maintained at a relatively hightemperature. Our invention is also based on the discovery that if thegas-forming substance used is readily oxidizable at a temperature belowthe melting point of the metal being cast a protective coating of oxidewill be formed between the mold and the metal. The term gas will be usedherein to include both gas and vapor.

WVhile our invention is not limited to the use of zinc as thegas-forming material used, zinc is especially suitable for use incasting ferrous metals in molds containing ferrous metals for the reasonthat zinc has a vaporizing point below the melting point of iron, andthus will produce a small amount of vapor or gas substantially in filmform lee-- tween the mold and the casting, when subj ected to the heatof the molten metal. This will operate to protect the mold and producesmooth castings. Some of the vapor or gas may be partially taken up bythe mold or the casting, or both, and if any remains after the castin isdischarged it will be precipitated as w ite oxide of zinc on the surfaceof the mold. The heated zinc metal at its surface will also be oxidizedby contact with the air.

Our invention may be so utilized as to make possible the pouring ofrepeated castings without repeating the treatment or it may be soutilized as to enable the molds to be quickly and easily treatedafter-each casting or pouring operation. The invention may be utilizedin connection with composition molds as well as metallic molds. With ourinvention the castings may be easily discharged from the mold as soon asthey have set sutlicientl y to retain their form or they may bepermitted to remain in the mold as long as desired, whether the mold ishot or cold, without injuriously affecting the surface of the matrix oradhereing thereto.

In carrying out our invention it is desirable to provide only a smallvolume of gas at each casting operation, since an excess of gas maycause pittingand the production of rough, imperfect castings. 1th ourprocess we are able to control, within reasonable limits, the amount orrate of gas formation, either when the gas forming substance isincorporated in the body of the mold, or when it is located on themolding surface. If the gas forming substance is incorporated in thebody of the mold, the heat from the molten metal, when it comes incontact with the molding surface, will cause the formation of a limitedamount of gas, and both during the casting process and in the interim between successive castings the gas forming substance will automaticallyapproach theheated molding surface and thus replenish the supply of suchsubstance where it is needed. Also the oxide of the gas forming materialwill be produced and form a surface coating on the mold which will tendto reduce the amount of the gas formed. If the oxide is itselfgasifiable, it will generally only be so at a higher temperature thanthat at which the oxide is formed and the amount of gas produced fromthe oxide will be comparatively small. In this way the supply of the gasforming substance to the surface of the mold is automatically regulated.If, on the other hand, the gas forming substance is located only on themolding surface, the amounts of gas that are successively formed may becontrolled either by regulating the amount of the gas forming substanceplaced on the surface, or by depositing with it or upon it a suitableheat insulating material, such as lamp black or zinc oxide.

In carrying out our invention we preferably use molds having metal inthe material surrounding the matrix of the mold, and for the protectivesubstance we preferably use a metal, or a composition of metals, ormetal compounds, which may be generally termed metalliferous substances,that will alloy with, or have an affinity for, or an ionic or electricattraction for, the substance of which the body of the mold is wholly orpartiall composed. The substance used for pro ucing the gas must be ofsuch a character that it will gasify at a temperature below the meltingpoint of the metal to be cast, inasmuch as we rely upon the heat of themolten metal to produce the gas. Preferably the vaporizing point of thegas forming substance should be above the maximum temperature at whichthe mold should be mai1ntained inorder to produce soft, perfect castingsand below the temperature of the molten metal to be cast. Anymetalliferous material may be used that will gasify or vaporize withinsuch a temperature range and produce a gas at the temperature of themolten metal. The selection of the gas forming substance will thereforedepend upon the melting point of the metal to be cast. For instance, ifbrass is to be cast, gas forming substances having relatively lowgasifying points should be used, such as cadmium and zinc chloride. Incasting iron, materials such as zinc, cadmium, magnesium and barium maybe used. If high speed steel is to be cast, it may be found desirable touse zinc, barium or bismuth as the gas forming material.

\Ve preferably use metalliferous materials that Willalloy with or beabsorbed by or have an affinity for the material of which the mold iscomposed, so that the gas forming substance may be incorporated in themold or will adhere thereto and thus insure a suitable supply of gas ateach casting operation. We therefore find it preferable to use zinc asthe gas forming material for molds containing iron when used forproducing castings of metals having high melting points, since the zinchas an afiinity for and is electro positive to the iron and willautomatically distribute itself under the action of the heat of themolten metal so as to keep the molding surfaces of the mold suppliedwith the proper amount of zinc, and will form zinc oxide over themolding surfaces. Whether the gas forming substance used will alloy withor be absorbed by the mold material, or merely has an aflinity therefor,it may be deposited on the molding surface in sufficient quantity toform the required amount of gas at each casting operation in makingrepeated castings.

If the mold material and gas-forming substance are such that the formerwill absorb the latter, as when iron molds are used with zinc as the gasforming material, the mold may be impregnated with the gas formingmaterial by submerging it in the molten metal preferably until the moldat its surface has become saturated therewith.

The mold is then removed from the molten metal and all the surplusfree'metal brushed from the surfaces, when it is ready for use in makinga large number of castings.

When the gas forming material is applied to the surface of the mold, itmay be deposited thereon by directing it in a gaseous condition againstthe molding surface, where it will congeal in the form of a powder orform a smooth surface coating, depending on thetemperature of the mold.Also the molds may be placed in a vapor of any of the metals mentioned,which will at the same time surface the mold with the gasiliable metaland the oxide of the metal. If the atmospheric oxygen has opportunity tocompletely burn the heated vapor then only the oxide will be depositedon the mold or the oxide of any of the metals mentioned may be depositedon the mold in any suitable wa The oxide may be partially reduced eitherby the reducing action of the molten iron and carbon of the iron, by thecarbon deposited as a coating, or by a reducing flame or it may remainin the form of an oxide and act as an eflicient neutral heat insulatorand protect the metal of the mold.

When the mold is formed of a composi-- tion of one or more materials,such gas forming material or materials should be selected as may beabsorbed by one or more of the ingredients of which the mold iscomposed, if the protective material is to be incorporated within themold as distinct from being applied to the surface thereof. Compositionmolds may be formed of a variety of materials. We have, however, foundit preferable to form composition molds of mixtures that contain clay asone of the ingredients. To the clay may be added one or more metalswhich will melt during the calcination of the clay. The protectivematerial selected, if it is to be incorporated within the mold, maytherefore be such that it will be absorbed by the clay or it may be suchthat it will form an alloy with or have an afiinity for one or more ofthe metals incorporated in the mold. The composition mold may thereforebe formed from a mixture of clay, iron, nickel and other materials, ifdesired. Molds formed of clay and nickel or of clay and iron we havefound will take up or absorb a large quantity of zinc and will deliverit to the molding surface in the same regulative way that the iron moldswill control the zinc supplvto their molding surfaces.

The protection afforded to the mold itself by the use of our process isof special importance in the use of composition molds, as the protectionthus provided prevents the molten metal from attacking anddisintegrating the mold materials, thus materially adding to the life ofthe molds.

The protective material may lee-incorporated in a composition mold bygasifying the protective. material preferably in a closed receptacle soas to exclude air and prevent oxidization of the protective material,and thus causing absorption of the gas-forming material, which uponchilling will be deposited as a solid within the body of the mold.Composition molds may also be coated with suitable gas formingsubstances in the same manner that the iron molds may be coated, asdescribed above.

Our invention contemplates the deposit of the protective material at ornear the molding surface, that is, in a location where it will have anactive protective relation to the mold or the molten metal inserted inthe mold, and includes broadly at the surface, on the surface, or withinthe material surrounding the matrix, but in each case located in aposition where it will function in its action as between the mold andthe metal of the casting while the casting is contained within the mold.

lVhether the gas producing substance is incorporated in any of the abovedescribed molds or,..-used as a surface coating, the amount of thegasification produced by the heat of th molten metal may be regulated bydepositing with or upon the gas-forming material a heat insulatingmaterial, such as lamp black or other similar material, thatwill notchemically react deleteriously on the materials of the mold, on the asforming substance, or on the metal to e cast in the mold. When lampblack is used, it may be deposited on the surface by means of anincomplete combustion flame produced from a hydrogen carbon gas. Whenthe mold is coated as distinct from being impregnated with th gasforming substance, the heat insulating material may be deposited on themold over the gas formim substance, or it may be deposited with the gasforming substance. Thus lamp black, or graphite, may be used to coverthe coating of the gasifiable mate-rial or it may be deposited with thegasifiable material.

By the us of our invention in connection with the casting of ferrousmetals, the castings may be made in heated ferrous molds, and ejected,if desired, while the interior of the casting is still in a moltencondition, or ferrous castings may be made in permanent ferrous metalmolds, either with or without preheating, and the casting left in themold until it has hardened throughout. In either case the inventionprovides a perfect separating means between the casting and the moldwhich enables assured delivery of all parts of the casting from themold, even though some of the surfaces of the casting may be drawn overor parallel with the surfaces of the mold.

Since gas forming substances such as we propose to use prevent theadherence of molten metal to metal, or of molten metal to calcined clay,ladles, crucibles, troughs, spouts and other devices or parts offurnaces used in manipulating certain metals, such as iron, brass, etc.,while in a molten state, may be treated with substances, such as zinc,magnesium, cadmium, etc., or their oxides and free flow and completedeliver of the metal from the devices will be assur We claim 1. Theprocess of preventing adherence of a metal casting to a mold, whichconsists in treating the mold with a metalliferous substance and formingbetween the mold and the casting a gas from the metalliferous substanceby the heat of the metal cast.

2. The process of preventing adherence of a metal casting to a mold,which consists in treating the molding surfaces of the mold with ametalliferous substance and forming between the mold and the casting agas from a the metalliferous substance by the heat of the metal cast.

3. The process of preventing adherence of a metal casting to a mold,which consists in surfacing the molding surfaces of the mold with ametalliferous substance and gasifying the metalliferous substance at themolding surfaces by the heat of the metal cast.

4. The process of preventing adherence of a metal casting to a mold,which consists in incorporating in the mold a metalliferous substanceand gasifying a portion of the metalliferous substance at the moldingsurfaces by the heat of the metal cast.

5. In the process of casting metals, treating the molding surfaces witha metalliferous substance having a gasifying point below the meltingpoint of the molten metal cast and forming a gas from the metalliferoussubstance at the molding surfaces by the heat of the metal cast.

6. In the process of casting metal, surfacing the molding surfaces ofthe mold with a metalliferous substance having a gasifying point belowthe temperature of the molten metal and forming a gas from themetalliferous substance atthe molding surfaces by the heat of the metalcast.

7. In the process of casting metals, incorporating in the moldscontiguous to their molding surfaces a metalliferous substance having agasifying point below the temperature of the molten metal and forming agas from the metalliferous substance at the molding surfaces by the heatof the metal cast.

8. In the process of casting metals, the steps of incorporating ametalliferous substance in the molds and gasifying successively portionsof the metalliferous substance by the heat of the molten metal formingthe castings.

9. In the process of casting metals, the steps of incorporating agasifiable material within the surface of the mold and forming a gaseousfilm over the molding surface by the heat of the metal cast.

10. In the process of casting metals, the

,steps of inconporating gasifiable material matinee within the surfaceof the mold and forming afilm of gas from the gasifiable material.

located at the molding surface by the heat of the metal cast. I

11. In the process of casting metals, the steps of incorporatingagasifiable material within the surface of the mold and forming a film ofgas from a portion of the gasifiable material at the moldlng surface bythe heat of the metal cast and replenishin the gasifiable material atthe surface 0 from the gasifiable material incorporated in the mold.

12. In the process of casting metals, the steps of incorporating a,gasifiable material within the surface of the mold, forming a film ofgas at the surface of the mold from the portion of the gasifiablematerial located at the moldin surface by the heat of the metal cast int e mold, gasifyin other portions of the gasifiable material locatedcontinguous to the surface of the mold and so lidif ing the last namedportions of the gasthe mold ifiab e material at the surface of the moldimmediately on delivery of the casting from the mold.

13. In the process of casting metals, the steps of incorporating agasifiable material in the mold by absorption, forming a gaseous filmbetween the molding surface and the metal cast in the mold by the heatof the molten metal, and replenishing the molding surface with thegasifiable material by absorption of portions of the gasifiable materialcontiguous to the molding surface.

14. In the process of casting metals, the steps of incorporating agasifiable material within the surface of the mold, forming a film ofgas over the molding surface by the heat of the molten metal, andautomatically replenishing the molding surface with gasifiable materialfrom the gasifiable material contiguous to the molding surface byvaporization produced by the heat of the metal cast.

15. In the process of casting metals, the steps of incorporating agasifiable material in the mold by absorption, forming a film of gasover the molding surface by the heat of the metal cast and regulativelyreplenishing the molding surface with the gasifiable material from thegasifiable material incorporated in the mold.

16. In the process of casting metals, the steps of impregnating the moldwith a gas forming substance and a heat insulating material and forminga gas from the gas ill) forming substance between the metal of themolding surface with a heat insulating material and gasifying a portionof the gasifiable material located at the molding surface b the heat ofthe metal cast.

19. n the process of casting metals, the steps of incorporating agasifiable material within the surface of the mold, coating the.

molding surface with a heat insulating material. gasifying thegasifiable material lo cated at the molding surface and regulating bythe heat insulating material the replenishment of the gasifiablematerial to the molding surface.

20. In the process of casting metals in molds containing a metal, thesteps of treating the molding surfaces with a metalliferous material andforming a gas from the metalliferous material by the heat of the metalcast.

21, In the process of casting metals in a mold containing metal, thesteps of incorporating a metalliferous material in the mold and forminga gas from the metalliferous material by the heat of the metal cast.

22. In the process of casting metals in a mold containing iron, thesteps of treating the mold with a metalliferous substance and forming 'agas from the metalliferous substance by the heat of the metal cast.

23. In the process of casting metals in iron molds, the steps oftreating the molds with a metalliferous substance and forming a gas fromthe metalliferous substance by the heat of the metal cast.

24. In the process of casting metals in iron molds, the steps oftreating the molds with zinc and forming a gas from the zinc by the heatof the molten metal cast.

25. In the process of casting metals in iron molds. the steps ofincorporating zinc in the mold and gasifying successively portions ofthe zinc by the heat of the molten metal cast.

26. In the process of casting metals in iron molds, the steps oftreating the molds with a metalliferous substance and a heat insulatingmaterial and forming a gas from the metalliferous substance by the heatof the metal cast.

27. In the process of casting metals in iron molds, the steps ofincorporating a metalliferous substance in the mold, coating the moldingsurface with a heat insulating material and gasifying sucessivelyportions of the metalliferous substance at the molding surface.

28. In the process of casting metals in in the molds and coating themolding surfaces with heat insulating material and gasi- 'fyingsucessively portions of the zinc at the molding surfaces by the heat ofthe metal cast. I

29. In the process of casting metals in iron molds, the steps ofincorporating zinc in the molds, coatin the molding surfaces with lampblack and forming films of gas from the zinc. at the molding surfaces bythe heat of molten metal of successive castmgs.

30. In the procem of casting metals in molds, the steps of incorporatinga metalliferous substance in the mold and coating the molding surfacewith a carbonaceous ma terial, and forming a gas from the metalliferousmaterial by the heat of the molten metal cast.

31. The process of preventing the adherence of a metal casting to ametal mold, which consists in incorporatingowithin the surface of themold a material oxidizable at a temperature below the melting point ofthe metal.

32. The process of preventing the adherence ofa metal casting to a mold,which consists in treating the mold with a material that will form anoxide over the surface of the mold by heat produced by the metalcastings,

33. The process of preventing the adherence of a metal casting to amold, which consists in treating the mold with a material that will forman oxide over the surface of the mold upon the removalof the castingfrom themold.

34. In the process of casting a metal the steps of incorporating withinthe surface of the mold a material that will form successively layers ofits oxide on the molding surface upon the removal of successivecastings.

35. In the process of casting the metals the steps of treating the moldwith a material that will form an oxide on the surface of the moldbetween successive castings, and coating the mold with a heat insulatingmaterial between the successive castings.

36. In the process of casting metals the steps of treating the mold witha metal, heating the mold, and forming an oxide of the metal over thesurface of the'mold.

37. In the process of casting metals the steps of incorporating a metalin the mold, and forming successively layers of the oxide of the metalover the molding surface by heat produced from the successive metalcastings.

38. In the process. of casting metals the steps of treating the moldwith a metal, maintaining the mold at a relatively high temperature, andforming a layer of oxlde of the metal over the molding surface.

39. In the process of casting metals the steps of treating the mold witha gasifiable substance, maintaining the mold at a relatively hightemperature, and forming a film of gas-from the substance by the heatproduced by the molten metal.

40. In the process of casting metals the steps of treating the mold witha metalliferous substance, coating the molding surface with a heatinsulating material, and maintaining the mold at a relatively hightemperature below the melting point of the metalliferous substance.

41. Ihe process of preventing the adherence of a metal part of a mold\toa casting which consists in treating the mold with a metal and itsoxide.

42. In the process of casting metals in molds, forming a -aseousmaterial at the surface of the molds by the heat of the metal, andoxidizing a portion of the gaseous material to form a coating of theoxide of the gaseous material on the molding surface of the mold.

43. In the process of casting metals, forming a gas from a material atthe molding surface of the mold by the heat of the metal, forming theoxide of the material by the heat and the oxygen of the air to form aprotective coating on the surface of the mold, and again forming a gasfrom the material in each subsequent casting operation.

44:. In the process of casting metals in molds, treating the mold with amaterial that will gasify and form an oxide below the temperature of themelting point of the metal cast in the mold and gasifying the materialby the heat of the metal of the casting and depositing the oxide uponthe removal of the casting.

45. The process of preventing adherence of a metal to a casting whichconsists in incorporating within the surface of the mold a material thatwill produce a gas when heated by the molten metal.

46. In the process of casting metals, impregnating the mold with ametalliferous material having a boiling point below the melting point ofthe metal cast in the mold in proximity to the molding surface.

47. In the process of casting metals in molds, impregnating the mold inthe vicinity of the surface of the matrix with zinc.

48. In the process of casting metals, treating the mold with zinc toprevent adherence of the casting to the mold.

49. In the process of casting metals, treating the mold with a materialcontaining zinc to prevent adherence of the casting to the mold.

50. In the process of casting metals, impregnating the mold with ametalliferous material to prevent adherence of the casting to the mold.

5I. In the process of casting metals in neeaoee molds having metallicmolding surfaces, impregnating the surface of the mold with a materialthat will prevent adherence of the metal cast to the metal of the mold.

52. In the process of casting metals in molds containing metal,impregnating the metal of the mold with a material that will render themetal that forms the casting neutral in its effect on the metal in themold.

53. In the process of casting metals in molds-containing metal,impregnating the contacting surfaces of the mold and the casting wlth amaterial that will neutralize the injurious effects between the metalsof the casting and the mold.

54:. In the rocess of casting metals in molds containlng metal, imprenating the contacting surfaces of the mo d and the casting with aprotecting metalliferous material.

55. In the process of casting metals in molds containing metals,impregnating surfaces of the mold and the casting with a protectingmaterial containing zinc.

56. In the process of casting metals in molds containing metals,impregnating the contacting surfaces of the mold and the casting 'with aneutralizing material containing zinc, and ejecting the castingimmediately after the casting has been formed.

57. The process of preventing adherence of a metal casting to a mold,which consists in incorporating in the mold a metalliferous substanceand gasifying a portion of the metalliferous substance by the heat ofthe metal cast, and ejecting the casting immediately after the castinghasbeen formed.

58. In the process of casting metals, treating the mold with ametalliferous substance, coating the molding surface with a heatinsulating material, and maintaining the mold at a substantially uniformand relatively high temperature below the melting point of themetalliferous substance, and ejecting the casting immediately after thecasting has been formed.

59. In the process of casting metals in molds containing metals,impregnating surfaces of the mold and the casting with zinc.

60. In the process of casting metals, treating the molding surfaces ofthe mold with a metalliferous substance having a boiling point below themelting point of the metal cast and forming a gas from the metalliferoussubstance by the heat of the metal cast.

61. In the process of casting metal, incorporating in the mold ametalliferous substance having a boiling point below the temperature ofthe metal and forming a gas from. the metalliferous substance by theheat of the metal cast.

62. In the process of casting metal in molds containing a metal,treating the molding surface of the mold with a metalliferous substanceand forming a gas from the metalliferous Substance by the heat of themetal cast.

63. In the process of casting metals, impregnating the mold with ametalliferous material that will prevent the adherence of the metal tothe mold during repeated castin operations.

64. n the process of castin metals, impregnating the mold in thevicinity of the molding cavity with a meta-lliferous material that willprevent the adherence of the metal to the mold during repeated castingoperations.

65. In the process of casting metals in molds containing metals,impregnating the metal of the mold with a quantity ofneutralizingmaterial sufiicient to prevent adherence of the casting to the moldduring repeated casting operations.

66. In the process of casting metals in molds containing iron, treatingthe molds with a metalliferous substance and forming a gas from themetalliferous'substance by the heat of the metal cast.

67. In the process of casting metals in molds containing iron, treatingthe molds with zinc and forming a gas from the zinc by the heat of themolten metal'cast.

68. In the process ofcasting metals in molds containing iron.incorporating zinc in the mold and gasifying successively portions ofthe zinc by the heat oithe molten metal cast. I

69. In the process of casting metals in molds containing iron. treatngthe molds with a metalliferous substance and a heat insulating materialand'forming a gas from.

72. In the process of casting metals in I molds containing iron.incorporating zinc in the molds, coating the molding surfaces with lampblack and forming films of gas from the zincat the molding surfaces bythe heat of molten metal of successive castings.

73. The process of preparing a mold containing metal near the surface ofthe matrix mold to the metal casting formed in the mold, which consistsin depositing a protective material containing zinc near the surface ofthe matrix of the mold.

7 4. The process of preparing a mold containing a metal near the surfaceof the matrix of the mold to prevent the adherence of the mold to themetalcasting formed in the mold, which consists in depositing aprotective material containing a zinc oxide near the surface of thematrix of the mold.

75.v The process ofpreparing a mold containing a metal near the surfaceof the matrixof the mold to prevent the adherence of the mold to themetal casting formed in the mold, which consists in depositing vaprotective material containing metallic zinc and Zinc oxide near thesurface of the matrix of the mold.

76. The process of preparing a mold to prevent. the adherance of ferrousmetal castings to the mold while formed in the mold, the mold having aferrous metal near the surface of the matrix of the mold, which consistsin depositing a protective material containing zinc near the surface ofthe matrix of the mold. I

77. The process of preparing a mold to prevent the adherence of ferrousmetal castings to the mold while formed in the mold, v

the mold having a ferrous meta-l near the surface of thematrix of themold, which consists in depositing a protective material containingmetallic zinc oxide near the surface of the matrix of the mold.

78. The processof preparing a mold containing a metal near the surfaceof the matrix of the mold to prevent the adherence ofthe mold 'to themetal cast ng formed in the mold, which consists in depositing aprotective material containing metal .electro positive to the metal ofthe mold near the surface of the matrix of the mold. and

coatingthe surface of the matrix of the mold with a carbonaceousmaterial.

79. The process of preparinga mold con.- taining a metal near thesurface of the matrix of the mold to prevent the adherence of themold'to the metal castin'g'formed in the mold, which consists indepositing a protective materi al containing zinc near the surfa e ofthe matrix of the mold. and coating the surface of the matrix of themold with a carbonaceous material;-

80. The process of preparing a mold containing a metalnear the surfaceof the matrix of the mold to prevent the adherence of the mold to themetal casting formed in the mold. which conssits in depositing aprotective material containing zinc oxide near the surface of the matrixof the mold.

and coating the surface ofthe matrix of the mold with a carbonaceousmaterial.

81. The process of preparing a mold containing a metal near the surfaceof the in the mold, which consists indepositing a protective materialcontaining metallic zinc and zinc oxide near the surface of the matrixof the mold, and coating the surface of the matrix of the mold with acarbonaceous material.

82. The process of preparing a mold to prevent the adherence of ferrousmetal castings to the mold while formed in the mold, the mold having aferrous metal near the surface of the matrix of the mold, which consistsin depositing a protective material containing metal electro positive tothe iron of the mold near the surface of the mold, and coating thesurface of the matrix of the mold with a carbonaceous material.

83. The process of preparing a mold to prevent the adherence of ferrousmetal castings to the mold while formed in the mold, themold having aferrous metal near the surface of the matrix of the mold, which consistsin depositing a protective material containing zine near the surface ofthe matrix of the mold, and coating the surface of the matrix of themold with a carbonaceous material.

84%. The procem of preparing a mold to prevent the adherence of ferrousmetal castings to the mold while formed in the mold, the mold having aferrous metal near the surface of the matrix of the mold, which consistsin depositing a protective material containing metallic zinc and zincoxide near the surface of the matrix of the mold, and coating thesurface of the matrix of the mold with a carbonaceous material.

85. The process of preparing a mold containing a metal near the surfaceof the matrix of the mold to prevent the adherence of the mold to themetal casting formed in the mold, which consists in depositing aprotective material containing metal electro positive to the metal ofthe mold near the surface of the matrix of the mold, and coating thesurface of the matrix of the mold with lamp black.

86. The process of preparing a mold containing a metal near the surfaceof the matrix of the mold to prevent the adherence of the mold to themetal casting formed in l the mold, which consists in depositing aprotective material containing zinc near the surface of the matrix ofthe mold, and coating the surface of the matrix of the mold with lampblack.

87. The process of preparing a mold containing' a metal near the surfaceof the matrix of the mold to prevent theadherence of the mold to themetal casting formed in the mold, which consists in depositing aprotective material containing zinc oxide near the surface of the matrixof the mold, and coating the surface of the matrix of the mold with lampblack.

88. The process of preparing a mold containing a metal near the surfaceof the matrix of the mold to prevent the adherence of the mold to themetal casting formed in the mold, which consists in depositing aprotective material containing metallic zinc and zinc oxide near thesurface of the matrix of the mold, and coating the surface of the matrixof the mold with lamp black.

89. The process of preparing a mold to prevent the adherence of ferrousmetal castings to the mold while formed in the mold, the mold having aferrous metal near the surface of the matrix of the mold, which consists in depositing a protective material containing metal electropositive to the iron of the mold near the surface of the mold, andcoating the surface of the matrix of the mold with lamp lolaclr.

90. The process of preparinga mold to prevent the adherence of ferrousmetal cas ings to the mold while formed in the mold, the mold having aferrous metal near the surface of the matrix of the mold, which consistsin depositing a protective material containing zinc near the surface ofthe matrix of the mold, and coating the surface of the matrix of themold with lamp black.

91. The process of preparing a mold to prevent the adherence of ferrousmetal castings to the mold while formed in the mold, the mold having aferrous metal near the surface of the matrix of the mold, which consistsin depositing a protective material containing metallic zinc and zincoxide near the surface of the matrix of the mold, and coating" thesurface of the matrix of the mold with lamp black.

92. In the process of-casting metals in molds, treating the molds with aheated metalliferous substance.

93. In the process of casting metals in molds, treating the molds with aheated powdered metalliferous substance.

94:. In the process of casting metals in molds, depositing the heatedfinely divided metalliferous substance on the surface of th mold. I

95. In the process of casting metals in vmolds, treating the molds witha heated metallic oxide.

96. In the process of casting metals in molds, treating the molds with aheated powdered metallic oxide.

97. In the process of easing metals in molds, treating the molds withthe heated powdered oxide of a metal having a melting molds, depositingon the surface of the mold point below that of the metal cast in the afinely divided heated oxide of ametal havl0 mold. ing a melting pointbelow that of the metal 98. In the process of casting metals in cast inthe mold. 5 molds, treating the molds with the heated In testimonywhereof, we have hereunto oxide of a metal having a melting point be-Signed our names to this specification. low that of the metal cast inthe mold. HUBERT A. MYERS.

99. In the process of casting metals in ARTEEMES D. STRAW.

